Sit on chair or bench with can on floor. Place foot perpendicular
on can's side so foot's arch sits on top of side of can.

Execution

Push foot down gently onto can while rolling arch of foot
back and fourth on can. Roll foot back until can is under front
part of foot's arch. Roll foot forward until can is under rear
part of foot's arch. Continue to roll back and forth. Repeat
with opposite foot if prescribed.